The present invention relates generally to devices for interconnecting coaxial cable to CATV systems, and more particularly to surge protection devices that protect the integrity of electronic components positioned within interconnect devices from high voltage surges of electricity.
In the CATV industry, cable television signals are traditionally transmitted by coaxial cable. As the cable is extended through a distribution network, several types of electrical devices, such as filters, traps, amplifiers, and the like, are used to enhance the signal and ensure signal integrity throughout the transmission. It is therefore necessary to prepare a coaxial cable for interconnection to these devices in such a manner so as to ensure that the signal is not lost or disrupted.
In a traditional interconnection of the coaxial cable to the electrical device, the coaxial cable is attached in axially aligned relation to a conductive pin extending outwardly from the electrical device. The pin then transmits the signal from the coaxial cable to the electrical device. A conductive lead extending rearwardly from the electrical device carries the electrically treated signal to the distribution cable in the CATV system.
It is also necessary to terminate a coaxial cable distribution line at its end point. To terminate the coaxial cable, its central conductor is interconnected to a termination connector, such as a UMTR. The termination connector includes an input end, a body portion which defines a cavity, electrical components mounted within the cavity (for instance, a capacitor to dissipate the charge, and resistor for impedance matching purposes), and an end cap that terminates the connector. The central conductor of the coaxial cable is electrically attached to a pin extending outwardly from the electrical components. As used herein, xe2x80x9cconnectorxe2x80x9d will refer to either a termination type connector or any other standard coaxial cable connectors used in a CATV system.
On occasion, a high voltage surge may be transmitted through the coaxial cable, for instance, due to a lightning strike. If this high voltage surge is permitted to be picked up by the input pin and transmitted to the electrical device within the connector, the device would become inoperable due to the electrical components essentially melting or otherwise deteriorating as a consequence of the surge. A new connector would then need to be installed at the site of the surge.
It is therefore a principal object and advantage of the present invention to provide a cable connector having a device that provides an alternate path for high voltage surges of electricity in order to protect the integrity of any electrical components positioned within the connector.
It is an additional object and advantage of the present invention to provide a surge protection device that may be easily installed on an otherwise conventional cable connector.
It is a further object and advantage of the present invention to provide a surge protection device for a cable connector that is inexpensive to manufacture.
Other objects and advantages of the present invention will in part be obvious, and in part appear hereinafter.
In accordance with the forgoing objects and advantages, the present invention provides a conventional cable connector, such as a UMTR (Universal Male Terminator type connector), that further comprises an element for protecting the electrical components positioned within the connector from high voltage surges. The surge protection element comprises a ring that is positioned in circumferentially surrounding relation to the input pin that carries the signal being transmitted by the coaxial cable. The ring includes at least one, and preferably three prongs that extend radially inwardly therefrom and terminate in close, but non-contacting relation to the pin.
The ring portion of the surge protection element is positioned in contacting relation to a shoulder formed on the body of the cable connector, and is composed of an electrically conductive material, such as, but not limited to, brass. The coaxial cable, which is electrically interconnected to the head of the pin (it should be understood that there may be other common elements disposed between the coaxial cable and head of the pin, such as a tap), passes through the ring portion, adjacent the prong(s), but in non-contacting relation thereto, thereby forming a gap between the prong(s) and cable. If a high voltage surge of electricity is carried by the coaxial cable, such as might occur if it is struck by lightening, a spark will be formed in the gap between the prongs and the cable due to the conductive composition of the surge protection element. As a consequence, the high voltage surge will be transferred to the surge protection element which, in turn, will conduct the electricity to the body of the connector to which it is positioned in contacting relation. The body of the conductor will then carry the high voltage surge of electricity around the electrical components positioned within it, and ultimately to ground. Thus, the high voltage surge will not pass into the electrical components positioned within the connector.
The level of the surge which will trigger the spark to arc between the surge protection element and the coaxial cable may be selectively controlled by using such devices with varying length prongs extending radially inwardly. The closer a prong is positioned relative to the coaxial cable, the lower the voltage level that will cause the spark. The relationship between the size of the spark gap and the voltage level which will trigger a spark is well known in the art.